attoDRY800

cryo-optical table (closed-cycle)

Quantum optics experiments often require cryogenic temperatures in combination with optical access to the sample space. Most experimental setups contain numerous optical elements that need to be precisely arranged on an optical table to shape and prepare the incident light, as well as to efficiently collect and convert the emitted light from the sample. The available space on the optical table in such cases is of paramount importance to many complex setups.

The revolutionary concept and design of the attoDRY800 present the perfect solution to satisfy these demanding requirements: it consists of an ultra low vibration cold breadboard platform which is fully integrated into an optical table. The cryocooler assembly is located in the otherwise unused space underneath. This unique design ensures a free workspace and unobstructed optical access to the cold sample from all directions on the optical table via 4 side and 1 top window. Apochromatic objectives with high numerical aperture (NA=0.81-0.95) can either be integrated into the cryostat, into the vacuum shield, or

put in close working distance next to the optical windows from the outside. This ensures extremely low drifts and optimal collection efficiency.

Being a closed-cycle cryostat, the attoDRY800 is the perfect replacement for all helium flow cryostat setups, adding the huge advantage that it requires no liquid cryogens and thus minimizing running costs. In addition, a fully automated temperature control between 3.8 and 320 K conveniently enables unattended long measurement cycles.

Most other off the shelf closed-cycle cryostats suffer from severe vibrations at the sample location, which typically are in the range of many microns. Thanks to a proprietary vibration isolation technique (patent pending), the residual vibrations on the cold plate of the attoDRY800 were measured to be around 2.6 nm peak-to-peak (vertical direction) only. Hence, with the attoDRY800 even extremely sensitive measurements are possible. Its cold breadboard sample space is designed to host several of attocube’s patented nanopositioners, as well as complete microscope or photonic probe station solutions.

I have to say we are very pleased with the attoDRY800 and have collected a good deal of data already.

(University of Oxford, Department of Physics, Oxford, Great Britain)

CUSTOMER FEEDBACK

Dr. M. Kroner

The attoDRY800 setup is ideal for phase contrast microscopy as it allows free space optical access to the sample from both sides and makes it easily possible to investigate the transmitted light in momentum and real space excellent!

(Institute for Quantum Electronics, ETH Zurich, Switzerland)

CUSTOMER FEEDBACK

Dr. Heindel

Our group is working on quantum optics experiments exploiting deterministic quantum light sources based on semiconductor quantum dots. The two attoDRY800 systems will be used to probe the mututal two-photon interference of remote quantum emitter located in both cryostats. We are keen on the exciting experiments possible with these very stable cryostat systems.

(TU Berlin, Institute of Solid State Physics, Berlin, Germany)

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Note: All product specifications are based on a standard system. Optional items or upgrades, other configurations or customization maychange one or several of the indicated values. Specifications and other information subject to change without notice.

Decide on the table size

Customized Newport optical tables with metric M6 or imperial hole pattern are available with the following dimensions:(other table sizes and solutions for integration with existing optical tables available on request)

Choose location of cold breadboard

In order to optimally adapt the system to specific experimental needs, the location of the cold plate of the cryostat can be specified by the customer upon ordering. It can be placed as close as 200 mm to the long edge, as well as off-center with respect to the short edge on wider tables (depending on table size).

Ultra-short working distance

A popular option for flow cryostats is to bring the cold sample as close as possible to an ultra-low working distance window. This allows to flexibly use external optics with a very high angle of admittance, maximizing the collection efficiency via high numerical aperture objectives. The ultra-short working distance option (RT-USWD) is compatible with xyz positioners and xy scanner, and features a min. working distance of 2 mm (1 mm) with (without) cold window installed.

Article

Art. No.

RT-SWD option

1011252

RT-USWD upgrade

1013109

Add multiple degrees of freedom for sample motion

The attoDRY800 is predestined to host your choice of nanopositioners, be it linear, rotary, tilting or scanning stages. Combine many degrees of freedom, or more than one stack of positioners to fulfill all requirements of your application! With our dedicated ATC100 thermal link, we ensure a perfect thermalization of your sample that is straightforward to mount and easy to use.

Sample holders

For users that require a sample holder with electrical contacts, attocube offers PCB based sample holders with 12 contacts. There are different options available for the respective vacuum shrouds and positioner configurations.

Article

Art. No.

ASH/PCB/12

1005710

ASH/SWD

1012785

ASH/Zvar

1013136

ASH/PCB/12mini

1013138

Electrical and optical feedthrough options

Additional wiring can be provided upon ordering directly through the cryostat, with convenient electrical access at pin connectors close to the sample in vacuum for customer use. Additional wiring can be also provided upon pre-wired and interfaced directly to the cold plate.Retrofit extra wiring or optical feedthroughs are possible via electrical feedthroughs in an adapter ring at the bottom of the sample chamber.

Electrical & optical feedthrough options

Electrical access in vacuum

12 wires, terminated in vacuum

Pre-wired to cold plate

12 wires, low resistance, compatible with nanopositioners

Coaxial feedthroughs

2 or 4 SMA connectors

Fiber feedthroughs

1, 2 or 4 FC/APC or FC/PC connectors

attoCFM/800

complete cryogenic confocal microscope

For many years, attocube has been pioneering cryogenic confocal microscopy. With the introduction of the attoCFM series of confocal microscopes almost a decade ago, the optical investigation of single quantum devices on the sub-micron scale at low temperature suddenly became available as a standard tool for scientists worldwide. Today, the attoCFM/800 is once again redefining the state-of-the-art for low temperature confocal microscopy.

It combines the revolutionary concept of the world’s first cryo-optical table with integrated low temperature objectives and the external optics head of the attoCFM I. The researcher is provided with a complete cryogenic confocal microscope system which arrives in his laboratory fully integrated and tested. Accompanied by an on-site installation and hands-on training by our experienced optics experts, this will jump start your measurements, and enable useful research results in a minimum amount of time. For more information on the confocal microscope setup, please check the attoCFM I pages on our website or in our catalog.

attoDRY800 - Selected Measurements

Proven Low Vibrations

The interferometric measurements on the left show vertical & horizontal displacement data measured directly on the cold plate of the attoDRY800. The peak-to-peak vibrations in vertical direction are around 3 nm (4 nm), while in lateral direction they are around 2 nm (17 nm) in a bandwidth of 200 Hz (1500 Hz). This very efficient and unique low vibration design even allows for very sensitive optical measurements such as optical probe stations or high resolution optical spectroscopy on nanostructures.

Direction

Peak-to-Peak@200 Hz (1500 Hz)

RMS@200 Hz (1500 Hz)

vertical

3 nm (4 nm)

1.0 nm (1.1 nm)

horizontal

2 nm (17 nm)

0.6 nm (2.1 nm)

The FFT of the data on the right is shown above as well for both directions, vertical and horizontal respectively, at a bandwidth of 1500 Hz. The dashed line at 1 pm indicates the noise floor of the interferometer.

When dealing with optical microscopy at low temperatures, one pre-requisite of paramount importance is the spatial stability: scarce optical signals such as those from single photon sources often imply long acquisition times, and hence require conditions as stable as possible over extended measurement periods.

Temperature fluctuations and gradients, combined with mismatched thermal expansion coefficients among the parts, can jeopardize the acquisition of images over a range of temperatures or longer periods of time.

The LT-APO configuration of the attoDRY800 with cold apochromatic objectives has been expressly designed in order to optimize the stability performance.

Overall, this minimizes thermal drifts significantly compared to optics sitting at room temperature – be it in vacuum or outside of the cryostat:

no measurable drift over 40 h at base temperature, and up to 30 K

smaller by almost a factor of 20 compared to warm objectives over the full temperature range

Also, as shown in the picture on the left, vibrations are absolutely no concern since there is no measurable difference between cryocooler ON and OFF configuration even at ultimate resolution.

Polariton dispersion in strong coupling regime

The group of Prof. Atac Imamoglu (ETH Zurich) uses the attoDRY800 for phase contrast microscopy. The video to the left shows the polariton dispersion in the so-called strong coupling regime, measured via white light transmission. The x-axis represents the in-plane momentum k||, the y-axis the energy E. The time evolution is given by the exciton-cavity detuning. In the inset, the corresponding spectrum at k|| = 0 is shown.

Single Photon Generation with Controlled Polarization from InGaN Quantum Dots

The research groups led by Prof. R. Taylor & Dr. R.A. Oliver in the UK have successfully generated single-photons with polarized light emission and predefined polarization axis at temperatures spanning from around 5 K to above 200 K using InGaN quantum dots. These quantum dots offer several advantages, such as high experimental repetition rates in the range of GHz, and for their growth as a planar structure, a single routine without complex geometrical engineering.

The emission spectra of these quantum dots were characterized using micro-photoluminescence techniques, while the samples were kept cool inside an optical cryostat equipped with attocube positioners. This cryostat, the attoDRY800, is able to reach temperatures ranges from below 5 K up to even above 300 K with very good thermal and vibrational stability.

The single-photons generated by these quantum dots are bright enough to allow their optical properties to be measured even above 200 K, a temperature considered to be the Peltier cooling barrier. Hence, this suggests in principle, that these quantum dots could be applied in integrated electronic circuits. And thanks to the achievable polarization control, these quantum dots are good candidates for on-chip polarization encoding in quantum cryptography.

To know more about the work done by Robert Taylor, Rachel Oliver and their research teams, please visit their websites here: Robert Taylor and here Rachel Oliver.